Acoustic Neuroma

Acoustic neuromas are benign tumors that form on the auditory nerve, which leads from the inner ear to the brain and transmits sound and balance information. Acoustic neuromas are generally slow growing and may affect one or both sides of the head. Also known as vestibular schwannomas or neurilemmomas, these tumors begin in the cells that form a protective lining around the body’s nerve fibers.

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Symptoms

Symptoms may include:

  • Hearing loss, affecting one or both ears
  • Ringing in the affected ear (tinnitus)
  • Pressure or a feeling fullness in affected ear
  • Dizziness
  • Loss of balance
  • Facial weakness, paralysis or numbness, which occurs when the tumor presses on the adjacent facial nerve

The type and severity of symptoms depends on the size of the acoustic neuroma.


Cause and Risk Factors

There is no known cause for acoustic neuromas.

The tumors develop most often in people between the ages of 30 and 60, and in about 5 percent of cases are associated with a rare genetic condition called neurofibromatosis type 2 (NF2).

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Diagnosis

Early diagnosis of acoustic neuroma provides the best treatment options and outcomes. However, symptoms may not be present in the early stages when the tumor is small, or may be subtle enough that they are attributed to the aging process or more common middle-and inner-ear problems.

When a doctor suspects an acoustic neuroma, diagnosis generally begins with a thorough ear examination and hearing test. Computerized tomography (CT) scans and magnetic resonance imaging (MRI) are used to determine the location and size of the tumor.

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Treatments

A medical team with substantial experience in the identification and treatment of acoustic neuromas is highly recommended. The best course of treatment is dependent on the severity of symptoms and tumor size, as well as patient age, overall health and lifestyle.

Simple monitoring may be the best course of treatment when tumors are small, symptoms are mild, or in older patients. MRIs may be performed to track the growth rate at intervals determined by the doctor. If the patient’s condition changes, radiation or microsurgery may be considered.

Radiation may be recommended when tumors are small to medium-sized. Stereotactic radiosurgery (SRS) is a form of radiation therapy that precisely targets the tumors with high doses of radiation while sparing the surrounding tissues.

Microsurgery may be necessary, with the goal of preserving hearing and the facial nerve. The tumor’s size will determine which surgical approach is recommended for this expected outcome. When there is no hearing to preserve, an alternative microsurgery option can be performed, focusing on preservation of the facial nerve.

For some patients with acoustic neuroma, particularly those with neurofibromatosis type 2, chemotherapy may be an appropriate treatment as well.